This application claims priority under 35 U.S.C. xc2xa7xc2xa7119 and/or to 9901925-9 filed in Sweden on May 27, 1999; the entire content of which is hereby incorporated by reference.
The present invention relates to an arrangement for reorganising and/or connecting optical fibres in a limited or confined space. When handling optical fibres, and then particularly optical fibres included in optical fibre cables, it is necessary to be able to combine several optical fibre cables at a collecting point and there reorganise and/or connect together individual optical fibres in a sealed fashion.
It is known to bring several optical fibre cables together in a closed container for reorganising and/or connecting the fibres. Commercially available solutions for sealing the cable transits or lead-throughs of the container include sealing said transits with the aid of shrink hoses placed on the optical fibre cables, or sealing said transits with the aid of self-vulcanising tape wound on the optical fibre cables, said tape being wound around the cable to an appropriate size. One disadvantage with the use of shrink hoses lies in the primary requirement of heat. The hoses must either be heated electrically or with the aid of gas. The former often requires the provision of a power source at the place where the cables are to be connected, while the latter constitutes an explosion hazard. The drawback with self-vulcanising tape is that installation is operator-dependent and that addition material is often required when resealing a used container, such as a connecting box.
U.S. Pat. No. 5,224,199A teaches a connecting box intended for optical fibre cables and comprising a bottom part and a top part which can be joined to the bottom part, wherein the bottom part and the top part each include grooves which face one another and when said parts are joined one to the other define channels into which elastic plugs that carry optical fibre cables are inserted. The elastic plugs are slotted, so as to facilitate both fitting and removal of the cables and enable the elastic plugs to be first placed on the optical fibre cables, so that the top part of the box can be connected to its bottom part with the plugs carrying said cables placed in the channels between the box parts. Dismantling of the cable from the box is effected by first separating the top part of the box from its bottom part and then opening the plugs, which is easily done, and removing the plugs from the cables and therewith release the same.
U.S. Pat. No. 5,313,546 teaches the use of an hermetically sealed connection encapsulation intended for optical fibre cables and comprising a bottom part which includes seal-accommodating channels and a lid which is connectable to said bottom part, wherein the seals include holes for accommodating optical fibre cables inserted thereinto. The seals of this solution have also been slotted to facilitate insertion of the cables into the seals prior to fitting the seals into the channels in the bottom part of the encapsulation.
With the intention of facilitating handling of optical fibre cables in a limited or confined space, such as a closed space, for instance in a sealed fibre/cable connecting box arrangement for reorganising and/or connecting optical fibres in said cables, the closed space has been provided with means for guiding and coiling the cables prior to stripping respective cables and mutually separating the optical fibres enclosed therein. In addition to organising the cables in said space in an ordered and controllable fashion, the provision of means for guiding and coiling the cables in said confined space also ensures that essentially the same preparation lengths are obtained with respect to the different cables, regardless of the transit or lead through which they have been inserted into said space, while also enabling the bending radii of the optical fibre cables to be monitored. By providing the elastic transits, i.e. the cable seals between the cables and the closed space, such as a cable connecting box, to the closed space accommodating the optical fibre cables with a tapering opening, alignment of the optical fibre cables can be adapted with respect to coiling of the cables, therewith reducing the influence of the transit on said cables. The centre part of the tapering opening enables the optical fibre cable to be angled to some extent when placed in the transit without needing to influence the tightness of the transit against the cable and against said space. The taper in the centre part of the transit also enables cables of different diameters to be sealed effectively. The cable seals will preferably seal the incoming and outgoing cables against the ingress of moisture and water.
The object of the invention is to integrate an optical fibre handling function in the moulded bottom part of a cable connecting box in all essential aspects. The purpose of this function is to provide a unitary measurement for all optical fibre cable preparations on the one hand, and to hold an installed optical cable in position in the bottom part of the box and prevent uncontrolled bending of the cables and to seal the cable transits on the other hand.
The invention will now be described in more detail with reference to preferred embodiments thereof and also with reference to the accompanying drawings.